Thanks, Derek, I've never tried to remap keys before and hadn't seen the keyboard layout screen in a long time. My lock button was on when I got there, and I had to unlock to change anything. I wasn't sure how I was supposed to reassign that key, but I clicked on Reset and it put Home back where it should be. Since I hadn't been reassigning keys (intentionally), reset only affected the Home key. And I still don't know how setting up buttons make key reassignments, but all is well now.
Scott